Aspects of this disclosure relate generally to telecommunications, and more particularly to techniques for congestion control related to transmission of video data.
Video telephony (VT) involves real-time communication of packets carrying audio and video data. A VT device includes a video encoder that obtains video from a video capture device, such as a video camera or video archive, and generates video packets. Similarly, an audio encoder in a VT device obtains audio from an audio capture device, such as a microphone or speech synthesizer, and generates audio packets. The video packets and audio packets are placed in a radio link protocol (RLP) queue. A medium access control (MAC) layer unit generates medium access control (MAC) layer packets from the contents of the RLP queue. The MAC layer packets are converted to physical (PHY) layer packets for transmission across a communication channel to another VT device.
In mobile VT applications, a VT device, e.g., a receiving device, receives the physical layer packets via a wireless forward link (FL) (or “downlink”) from a base station (e.g., eNB) to the VT device as a wireless terminal (e.g., a user equipment, UE). A VT device transmits the PHY layer packets via a wireless reverse link (RL) (or “uplink”) to the base station. Each VT device includes PHY and MAC layers to convert the received PHY and MAC layer packets and reassemble the packet payloads into audio packets and video packets. A video decoder within the VT device decodes the video data for presentation to a user via a display device. An audio decoder within the VT device decodes the audio data for output via an audio speaker.
However, as wireless communication links, e.g., LTE links have varying channel capacities, the receiving device may encounter congestion problems due to various reasons. Therefore, there is a desire for proper congestion control at the receiving device such that the user experience is improved and/or optimized, for example, through avoiding the introduction of packet losses and picture freezes (playout).